Coats and Clark Professional Upholstery Thread is an extra strong thread for machine and hand sewing of upholstery and heavy-weight fabrics. It is 100% bonded Nylon and weather resistant. Use for sewing upholstery and slipcovers as well as repairing heavy duty items such as canvas bags and camping equipment. This 1500-yard king spool provided the equivalent of 10 conventional spools meaning less more time sewing and less down time changing empty spools.